It is recognised in the medical community that assessment of the movement of a subject, generally referred to as mobility, may be us as an indicator of medical conditions, and a lack of mobility carries an attendant risk of falling. It is also well known that the population of the world is ageing, and for people over the age of 65 falling is one of the serious problems, which causes injury, reduced quality of life and often death in seniors. The medical costs to the senior, the senior's family, and to public and private health care systems from these falls is devastating. Assessing the mobility and thereby the risk of falling is a significant tool for the prevention of falls and for the determination of the implementation of procedures, practices, and aids to improve mobility, activity and a better quality of life for the ageing seniors.
Vicky Scott, British Columbia Injury Research & Prevention Unit, Ministry of Health, Office for Injury Prevention, Victoria BC, Canada, et al., in 2008 published results of an exhaustive review of published studies that test the validity and reliability of fall-risk assessment tools, titled “Multi-factorial and functional mobility assessment tools for fall risk among older adults in community, home-support, long-term and acute-care settings”. The results indicated some 38 such different tools were considered, all of which show moderate to good validity and reliability. However, an ongoing study by Gabriele Meyer, University of Hamburg, Unit of Health Science and Education, Hamburg, Germany, et al., in 2005 to evaluate the clinical efficacy and consequences of different fall risk assessment strategies with 54 nursing home clusters, including 1080 residents, states that only three tools have been repeatedly evaluated in geriatric populations: the Tinetti Test, the Mobility Interaction Fall Chart and the Downton Index.
Many patents have taught methods and instrumented apparatuses related to measuring parameters for mobility, stability and walking, and devising systems to aid, correct and rehabilitate movement of subjects as related to their risk of falling. Nashner, in 1997 U.S. Pat. No. 5,623,944 and again in 2000 U.S. Pat. No. 6,010,465, teaches the use of mechanical treadmills instrumented with sensors connected to computers to measure a subject's walking gait. Sol, in 2001 U.S. Pat. No. 6,231,527, teaches the use of mechanical treadmills instrumented with sensors, plus the addition of several video cameras and mirrors, producing data related to weight-bearing forces on a subject's feet while walking in instrumented shoes as a method for analyzing walking difficulties and determining orthotic solutions. Adrezin, in 1996 U.S. Pat. No. 5,511,571, teaches using mechanical walking aids such as walkers, canes or crutches wherein the actual aids are themselves instrumented with sensors to measure force loads in those aids from which to measure the gait of a walking subject.
Many patents have taught methods and instrumented subjects related to measuring parameters for a subject's body mobility, stability and walking, and devising systems to aid, correct and rehabilitate movement of those subjects as related to their risk of falling. Ng, in 1998 U.S. Pat. No. 5,807,283, teaches use of a magnetic sensor strapped to the leg of a subject, plus additional instrumentation strapped to the subject's other leg or to a specialized shoe worn by the subject, from which data are transmitted to receiving and analysis systems to measure the speed and gait of the subject. Weir, in 1998 U.S. Pat. No. 5,831,937, teaches the use of a transponder worn about the middle of the subject's centre of mass, which transmits infrared and ultrasound pulses to receiver and computer systems, from which data gait, speed, cadence, step time and step length are determined for assessment of gait pathologies. Allum, in 1999 U.S. Pat. No. 5,919,149, teaches use of angular velocity transducers attached to the upper body of a subject, to detect the movement not of a subject's feet but of the subject's body swaying in angular position and velocity, plus specialized eyewear, from which data an operator may interpret balance or gait disorders. Amimian, in 2006 U.S. Pat. No. 7,141,026, teaches a similar body movement method as does Allum, but in particular uses a gyroscope sensor attached to the trunk of a subject for the measurement of the postural transitional speed and direction of the movement from which an operator can determine the time duration of postural transitions for actions like standing and rising from sitting, related to risk of falling.
Many patents have taught methods and instrumented subjects related to measuring parameters of a subject's feet movement relating to the subject's walking gait. Takiguchi, in 2007 U.S. Pat. No. 7,172,563, teaches using a microphone attached to a subject's body for picking up low frequency sounds from their feet, and an analyzer of the sounds transmitted through the subject's body while walking, from which gait characteristics of that specific subject can be determined. Hubbard, in 2002 U.S. Pat. No. 6,360,597, teaches the use of force-sensing sensors installed in a shoe insert worn by a subject, from which sensor electrical output data are analyzed for analysis of gait of a walking subject. Haselhurst, in 2007 U.S. Pat. No. 7,191,644, teaches the use of a pressure sensor and personal annunciator system installed in a shoe insole worn by a subject having difficulty walking, with which the system can tell the subject when the foot is contacting the floor, as a gait assistive device. Au, in 1989 U.S. Pat. No. 4,813,436, teaches the use of pressure sensors installed in the shoes or in shoe inserts worn by a subject, for measuring the subject's gait while walking, plus the use of video signals from two video cameras recording the motion of the subject who is wearing strategically placed visible markers such as on knees, elbows, and hips such that these data, along with the gait measurements, are presented to a practitioner to judge the subject's walking gait and, by overlaying these data on the video and gait of a “normal” subject, allows comparisons to be made.
The problem with all of the above methods is that they are invasive to the subject, are conducted in artificial testing environments, and that they present only data which subsequently require a skilled practitioner to interpret these data and draw conclusions as to the mobility of the subject, and in some cases to estimate the subject's risk of falling. To obtain an objective assessment, current fall risk testing systems and methods often use a 0-1 or 0-1-2 number scoring scale on each of 10 to 20 motion movements of a subject as assessed by an observer. These scores are totalled for a sum total number that describes an average risk of falling wherein a higher score indicates a lower risk of falling. For example, if in 20 movements, say, a subject scores 2 on each of 19 movements and 0 on one for a total score of 38, this result would normally be considered a low probability of falling.
Where the subject is an aged person or persons living in a senior's residence, home, long-term care or hospital environment the risk of falling is high. It is well known that these subjects are highly vulnerable to falling and that such falls often are devastating to the subject, their families and the providers of accommodations and care for them. The known techniques for assessing such risks do not lend themselves to such an environment where a large population has to be monitored on a continuous basis.
It is therefore an object of the present invention to provide a system, method and apparatus in which the above disadvantages are obviated or mitigated.